The applicant's successful and popular vehicle recovery system sold under the trademark LoJack® includes a small electronic vehicle locating unit (VLU) with a transponder hidden within a vehicle, a private network of communication towers each with a remote transmitting unit (RTU), one or more law enforcement vehicles equipped with a vehicle tracking unit (VTU), and a network center with a database of customers who have purchased a VLU. The network center interfaces with the National Criminal Information Center. The entries of that database comprise the VIN number of the customer's vehicle and an identification code assigned to the customer's VLU.
When a LoJack® product customer reports that her vehicle has been stolen, the VIN number of the vehicle is reported to a law enforcement center for entry into a database of stolen vehicles. The network center includes software that interfaces with the database of the law enforcement center to compare the VIN number of the stolen vehicle with the database of the network center which includes VIN numbers corresponding to VLU identification codes. When there is a match between a VIN number of a stolen vehicle and a VLU identification code, as would be the case when the stolen vehicle is equipped with a VLU, and when the center has acknowledged the vehicle has been stolen, the network center communicates with the RTUs of the various communication towers (currently there are 130 nationwide) and each tower transmits a message to activate the transponder of the particular VLU bearing the identification code.
The transponder of the VLU in the stolen vehicle is thus activated and begins transmitting the unique VLU identification code. The VTU of any law enforcement vehicles proximate the stolen vehicle receive this VLU transponder code and, based on signal strength and directional information, the appropriate law enforcement vehicle can take active steps to recover the stolen vehicle. See, for example, U.S. Pat. Nos. 4,177,466; 4,818,988; 4,908,609; 5,704,008; 5,917,423; 6,229,988; 6,522,698; and 6,665,613 all incorporated herein by this reference.
A typical VLU includes, inter alia, a receiver or a receiver and a transmitter combined as a transceiver, a transponder, and a microcontroller programmed to, among other things, control the operation of the transceiver and transponder to process messages received by the transceiver and to store the unique identification number of the VLU. A VLU power supply unit receives a nominal 12 volt signal from the vehicle and filters and regulates that input voltage to provide the appropriate voltage levels for the operation of the transceiver, the transponder, and the microcontroller.
When a vehicle is stolen, it is possible to disable the VLU by injecting into it a very high (e.g., 200 volt) input voltage. When subjected to such an input voltage, the power supply unit, the transceiver, the transponder, and/or the microcontroller (or individual components thereof) can be damaged rendering the VLU inoperable and unable to transmit the transponder signal.